O' Dempsey, o Diomasaigh
The name Dempsey comes from the Irish ‘diomasach’ meaning proud. The O’ Dempsey families were a powerful sept in Counties Laois and Offaly. The families were consistently pro-English in the time of Elizabeth 1. However they took the Irish side later in the seventeenth century. The Dempsey’s were also notable among the priests in penal times.